Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933362AbaBUNcP (ORCPT ); Fri, 21 Feb 2014 08:32:15 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47140 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932451AbaBUMvH (ORCPT ); Fri, 21 Feb 2014 07:51:07 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Lars Poeschel , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 3.11 084/121] tty: n_gsm: Fix for modems with brk in modem status control Date: Fri, 21 Feb 2014 12:48:28 +0000 Message-Id: <1392986945-9693-85-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> References: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Lars Poeschel commit 3ac06b905655b3ef2fd2196bab36e4587e1e4e4f upstream. 3GPP TS 07.10 states in section 5.4.6.3.7: "The length byte contains the value 2 or 3 ... depending on the break signal." The break byte is optional and if it is sent, the length is 3. In fact the driver was not able to work with modems that send this break byte in their modem status control message. If the modem just sends the break byte if it is really set, then weird things might happen. The code for deconding the modem status to the internal linux presentation in gsm_process_modem has already a big comment about this 2 or 3 byte length thing and it is already able to decode the brk, but the code calling the gsm_process_modem function in gsm_control_modem does not encode it and hand it over the right way. This patch fixes this. Without this fix if the modem sends the brk byte in it's modem status control message the driver will hang when opening a muxed channel. Signed-off-by: Lars Poeschel Signed-off-by: Greg Kroah-Hartman Signed-off-by: Luis Henriques --- drivers/tty/n_gsm.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 6422390..3ee7217 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1089,6 +1089,7 @@ static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) { unsigned int addr = 0; unsigned int modem = 0; + unsigned int brk = 0; struct gsm_dlci *dlci; int len = clen; u8 *dp = data; @@ -1115,6 +1116,16 @@ static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) if (len == 0) return; } + len--; + if (len > 0) { + while (gsm_read_ea(&brk, *dp++) == 0) { + len--; + if (len == 0) + return; + } + modem <<= 7; + modem |= (brk & 0x7f); + } tty = tty_port_tty_get(&dlci->port); gsm_process_modem(tty, dlci, modem, clen); if (tty) { -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/